A sheet for packaging so-called edible meat such as ham, sausage and fish paste products is generally processed as follows. First, the sheet is cut to a predetermined size. Next, the edges of the cut sheet are heat-sealed to each other to form a tubular casing. Subsequently, one open end (tip end) of the casing is sealed with a clip or the like to form a bag-like shape. Edible meat is packed in the casing, then the other open end (base end) is sealed with a clip, and thus the casing is hermetically sealed in a state of the casing with edible meat packed therein.
For the purpose of successfully performing the above-described operation, the sheet for packaging edible meat and the casing for packaging edible meat formed in a tubular shape by using the sheet are required to have a sufficient strength to withstand the packing pressure so that the sheet and the casing is not broken or torn (hereinafter, referred to as “ruptured”) at the time of packing edible meat.
In the production of, for example, ham or salami, edible meat is packed in a casing, and then processed or allowed to age in a state of being suspended with a hook or the like. In such a case, even when the internal pressure of the casing is uniform at the time of packing edible meat, the edible meat is moved downward by its own weight as the time elapses to increase the internal pressure in the lower part of the casing. Consequently, the lower part of the casing sometimes expands because of being unable to withstand the increase of the internal pressure.
Accordingly, in Patent Document 1, the present applicant has proposed a casing paper (sheet) for packaging edible meat, solving the above-described problems. The sheet described in Patent Document 1 is formed of a copolymerized polyester composite fiber and a hydrophilic fiber without using viscose, and is designed for a pressure of packing edible meat ranging from 1.4 to 2.8 kg/cm2.